Welcome! This forum has a treasure trove of great info – Scouters helping Scouters! Just a heads up, though - all content, information, and opinions shared on this forum are those of the author, not the BSA.
I don’t believe COR delegate lets you modify that. COR delegate I believe only gives you the same adult leader approval abilities of the COR. For updating the pin, you’d need to be a Key 3 position or a Key 3 Delegate position.
I’m also the Cubmaster. Sorry, I should have said that; I just said I’m the COR Delegate, because I presumed that lets me do anything other than change the executive officer and wouldn’t lack permissions needed for this.
I needed to go to my office last night and connect directly to my network (with an actual cable). I tried it with the different connection and succeeded.
Now, I’m back home. I tried again, and it worked. Obviously, there was something wrong with my laptop that got fixed by an update pushed from the direct connection to the network.